Util driver is not a performance critical driver and furthermore some
util services such as KVP can only handle one outstanding message
from the host. Turn off batched reading for util drivers.

Signed-off-by: K. Y. Srinivasan <k...@microsoft.com>
Reviewed-by: Haiyang Zhang <haiya...@microsoft.com>
---
 drivers/hv/hv_util.c |   10 ++++++++++
 1 files changed, 10 insertions(+), 0 deletions(-)

diff --git a/drivers/hv/hv_util.c b/drivers/hv/hv_util.c
index a0667de..a62a760 100644
--- a/drivers/hv/hv_util.c
+++ b/drivers/hv/hv_util.c
@@ -274,6 +274,16 @@ static int util_probe(struct hv_device *dev,
                }
        }
 
+       /*
+        * The set of services managed by the util driver are not performance
+        * critical and do not need batched reading. Furthermore, some services
+        * such as KVP can only handle one message from the host at a time.
+        * Turn off batched reading for all util drivers before we open the
+        * channel.
+        */
+
+       set_channel_read_state(dev->channel, false);
+
        ret = vmbus_open(dev->channel, 4 * PAGE_SIZE, 4 * PAGE_SIZE, NULL, 0,
                        srv->util_cb, dev->channel);
        if (ret)
-- 
1.7.4.1

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